1. Field of Invention
The invention relates to a device for forming stacks of bags which are individually supplied. The device has at least a first transport device with which individual bags are taken up, a collection point to which the bags are fed by the transport device and in which a stack of bags can be produced a release device with which the bags are released from the transport device and dropped at the collection point, and at least one separation device which can be inserted into or above the stack at the collection point to divide the stack into a first stack and a second stack. The invention also relates to a method of forming stacks with the inventive device.
2. Description of the Prior Art
Bags are produced individually in an apparatus for producing bags. Plastic bags are usually provided with welds and usually separated at the same time. For the production of paper bags, first tubes are formed from sheets of paper and then pieces of the tube separated. A bottom is formed at the leading end of each piece of paper tube.
The bags so formed are stacked in an apparatus for forming stacks, so that the bags are removed in batches and packaged and/or processed further.
Such an apparatus for producing stacks is disclosed in published patent application DE 30 40 021 A1. A transport device is shown which fixes an individual bag from above to the lower run of a suction tape by means of a negative pressure and draws the bag towards a collection point. The bag is detached from the suction belt by means of a separation device while a pressing device presses the bag down at the collection point. The bag is detached from the suction openings of the suction tape. Once, a stack with a desired number of bags has been formed in this way, a conveyor belt on which the stack has been formed moves them on. Then, a new stack is formed at a free collection point of the conveyor belt.
The disadvantage of this arrangement is that the feed rate and thus the speed of the bag-making machine is very limited. If the feed rate is increased, the previous stack may not beat a sufficient distanced at the beginning of the forming of the new stack. This disadvantage is acceptable In the manufacture of foil bags because the production speed is limited by other factors.
However, in the manufacture of paper bags where speeds of over 1,000 bags per minute may occur, this limitation due to the said stacking limitation is undesirable.
DE 20 2007 002 477 U1, therefore, provides two collection facilities, but this arrangement leads to a large space demands and is also likely to be expensive.